ot: problems

Wed Sep 17 18:56:17 MST 2014

Hello Michael,

I'm curious, did you buy this quad new or did you buy it used or is it a 
work computer owned by a company?  I get the feeling that you bought it 
used.

There's almost always a reason for failures and it's usually a problem 
that can be isolated.  If it's a part, it can be replaced.  If it's 
something else, it can be fixed.

When stuff like this starts to happen, it may be one of three things: a 
loose connection or a bad motherboard or a power supply.  Apple builds 
solid hardware but sometimes it gets abuse or just used in a poor 
environment with too much heat and/or moisture or just takes a physical 
beating - they are rather heavy.  Also quads, I believe, have water 
cooling.  I have seen at least one report of leaks.  That's usually easy 
to rule out if there's no leaks.

So where to begin?  Well, the pedant is back!

You may want to take some anti-static electricity precautions.  First, 
disconnect the Mac completely from all exterior cords, wires, etc.  Lay 
it on its side where there is plenty of light, a clean worktop area and 
a Phillips screwdriver.  As you have seen, it's easily taken apart, at 
least the easy pieces need only your hands.  Pull the fans out, take the 
video and other cards out, unhinge and pull the memory sticks out and so 
on until you are puzzled how to get the cooling shrouds out. (Don't do 
that.) Inspect everything.  Look for any corrosion.  Remove as much dirt 
and dust as you can with an air duster can (take care here, the these 
cans may contain hydrocarbons that are flammable and they should not be 
inhaled!).  If you use an air compressor, be gentle and use lower 
pressure less than 40psi.  What you can't get out with air, start with a 
clean microfiber cloth and wipe without generating static (i.e. don't 
rub hard).  Make sure all the connectors are clean and shiny before 
reassembling.

We call this clean and re-seat the boards.

Make sure you put the same memory sticks back into the same slots - it 
usually matters or makes a difference.  If you don't remember, read up 
on it from a manual, usually online at Apple.com.

Memory sticks are tricky because they often won't reseat properly 
without strong pressure.  First, make sure the middle slot on the memory 
stick is lined up with the ridge in the bottom of the connector.  The 
slots are offset from the middle on purpose, they are only supposed to 
go in one way.  (Having burned out a memory stick by forcing it in 
backwards, I can speak from experience! Won't do that again!) The way to 
handle this is to use two hands, with thumbs or your choice of fingers 
at each end of the board. Making sure the stick is aligned correctly in 
the connector; push FIRMLY down until both ends of the connector snap 
into the stick.  Main logic boards are epoxy and embedded fiber, are 
very strong and can take a little flexing without
hurting them.  Same with memory sticks.

Make sure the memory is seated well - it may take close inspection with 
a flashlight.  If the sticks are all the same size, then no stick should 
be higher than the lowest one.

OK, reassemble the computer.

Testing the power supply can be difficult.  It's easier with a common 
desktop PC because the power connector is almost always on top of the 
board and easily accessible.  It's not enough to test a power supply out 
of the computer because it won't be under load.

Here's how an expert taught me to test the power supply on a desktop PC 
(but not a Dell!)  Take a meter and set it to DC volts.  There will be a 
pair of test leads with pointed ends to poke at things.

You will push the points into the connector until it connects to the 
metal of the connector sleeve.  Connect the common lead to a black 
wire's connector.  Test all the colored wires with the positive (usually 
red) meter probe. Here are the correct voltages for a PC:

Yellow		+12 Volts
Red		+5  Volts
Purple		+5  Volts
Orange		+3.3Volts
Green		don't test; this turns on the PC when shorted to black
White		-5  Volts
Blue		-12 Volts
Gray	I think this one is for the power-is-on LED
Brown   Not sure about this one

The important thing is that the voltages are nearly correct when the 
computer is powered on because that shows the power supply to be good 
when under a load.

One other thing - sometimes a part can acquire a static charge which 
won't dissipate properly.  The only remedy for this is to wait until it 
discharges (unless you are a motherboard repair person).

Things that have hurt my equipment is usually near lightning strikes. 
Lost one treasured Mac to a lightning strike that hit the phone lines. 
Took out phones for three stories above me.  Mac did not fail right away 
but eventually lost it  (sniff :( ).   Lightning strikes across the 
strike have taken out a couple ethernet ports over the years even though 
my equipment has always been on a UPS.  Strong strike will generate an 
EMP which is sometimes picked up by a network wire of a resonant length. 
  Usually, though, it's not serious but if the storm is bad, we'll turn 
off the electronics until it's past.

I apologize for the length of this, but you get the idea of the lengths 
I go to fix things.

Best of Luck and let me know how it turns out if you have the time,
As always, take care.
Jon

On 09/17/2014 06:27 PM, Michael Havens wrote:
> first certain keys sometimes don't work unless I hold the key down and
> then after a time the character will appear (sometimes multiple times).
> So it was recomended I pop the keys off and clean under them. So I do
> and it doesn't fix the problem. No problem. I'll stick it under my table
> and attach wireless periphiels too it. Then I need to go visit my kids.
> So I figure I'll suffer with the keyboard problem. The day I left for
> Miami (at the airport) the hardware internet switch would not turn on.
> Then, after I arrive in Miami, I turn on the computer and a notice
> appears at boot saying that 'the cooling fan is not operating properly'.
> What problem do you think is causing this? I called my dad and he said
> it sounds like the hard disk is going bad. He also said maybe the
> keyboard controller (because of the internet switch).
> :-)~MIKE~(-:
>
>
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